Besides the obvious appearing in fake Red John cases and appearing to know absolutely nothing making him look more and more like he is trying to hide that he isn't. When Red John tells Jane the poem, the voice doesn't sound disguised, but rather like it's being changed just slightly because his mouth is covered, to me that voice sounds like a smaller male like Brett, I wouldn't say it's the guy running the religion because his voice would have been deeper, but it's not a female, that voice was definitely a male with a lighter voice.